Cartridge feeding mechanism for fixedbarrel, slide-operated guns



Dec. 7, 1965 J. L.. LocHHl-:AD

CARTRIDGE FEEDING MECHANISM FOR FIXED-BARREL, SLIDE-OPERATED 5 Sheets-Sheet l GUNS Filed March 23 1964 INVENTOR ghn L Lunhheu e. ATTORNEY Dec. 7, 1965 J. L. LocHHEAD 3,221,603

CARTRIDGE FEEDING MECHANISM FOR FIXED-BARREL. SLIDE-OPERATED GUNS Filed March 23, 1964 3 Sheets-Sheet 2 fig] & 66 74 82 72 e4 76 64 6o igz@ |06 fla Eig"- 28 -lOO Y H2 El- ATTORN EY Dec. 7, 1965 L.. LocHHEAD 3,221,603

J. CARTRIDGE FEEDING MECHANISM FOR FIXED-BARREL, SLIDE-OPERATED GUNS Filed March 25, 1964 3 Sheets-Sheet 5 INVENTOR JnhnLLunhhEu ATTORNEY United States Patent C) 3,221,603 CARTRIDGE FEEDING MECHANISM FOR FHXED- BARREL, SLIDE-OPERATED GUNS John L. Loehhead, Springfield, Mass., assigner to the United States of America as represented by the Secretary of the Army Filed Mar. 23, 1964, Ser. No. 354,183 7 Claims. (Cl. 89-33) (Granted under rEitle 35, U.S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to automatic guns in which a slide is longitudinally reciprocated to control the opening and closing lof the breech and is more particularly directed to improved means for utilizing the reciprocation of the slide to actuate mechanism for feeding ammunition into position to be rammed into the firing chamber during the closing of the breech.

Although the requirements of modern warfare create a constant demand for weapons of larger caliber and increased fire-power, considerable diiculty has been encountered in providing these characteristics in those automatic guns intended for installation in such military vehicles as tanks and aircraft. For one thing, the greater length of these larger caliber guns cannot be readily accommodated in the extremely small compartments generally provided for the operator of these vehicles. While the concept of locating the gun outside the operators compartment for remote control firing has permitted a desirable increase in the size of many of these guns, such expedient has not been successfully extended to those guns wherein the ammunition is fed thereto in the form of a linked belt of cartridges which must be advanced along a transverse feedway in the receiver during each successive firing cycle. In belt fed guns of this type, it is essential that the operator have complete access to the feedway of the gun in order to permit the handling of the cartridge belt required in the loading and unloading thereof as well as in the correction or elimination of any feeding stoppages or malfunctions. Accordingly, these belt fed guns must be mounted so that at least the feedway and the portion of the receiver rearwardly thereof will lie within the reach of the operator. However, in current guns of this type, the required access to the feedway results in a receiver whose length interferes with the unrestricted freedom of movement so essential for optimum handling of the controls of the vehicle.

Although the prior art has attempted to reduce the distance between the rear end of the receiver and the rear end of the transverse feedway therein through the expedient of transfer-ring the function of operating the cartridge feeding mechanism from the bolt to a reciprocating slide utilized to actuate the bolt, it was found that the relatively complex connection required between the slide and the cartridge feed mechanism invariably nullitied the benefits derived from the reduction in the length of the bolt.

Accordingly, it is a general object of this invention to provide a simple and rugged cartridge feeding mechanism for a relatively large caliber automatic gun Iof the type wherein the bolt is actuated by a reciprocating slide to strip the leading cartridge from a linked belt and ram such cartridge into the iiring chamber in the barrel.

It is a further object of this invention to locate the aforesaid cartridge feeding mechanism in a manner which will permit a substantial reduction in the length of the receiver rearwardly of the transverse feedway therein.

A more specific object of this invention is to provide 3,221,603 Patented Dec. 7, 1965 cartridge feeding mechanism, as aforesaid, wherein the linkage between the slide and the cartridge feeding pawls is accomplished with a minimum number of parts.

Another object of the present invention lies in the provision of a cartridge feeding mechanism, as aforesaid, wherein the components thereof do not extend rearwardly of the feedway in the receiver.

It is a final object of this invention to provide a cartridge feeding mechanism, as aforesaid, wherein the slide can be readily removed from the gun without the necessity for the prior disassembly of the cartridge feeding mechanism.

It has been found that the foregoing objects can be achieved by improved means for converting the longitudinal reciprocation of the slide to a transverse reciprocation of the cartridge feed mechanism. Such means essentially comprises a U-shaped actuator pivotally mounted in the receiver to straddle the breech end of the barrel. One leg of the actuator is provided with a forwardly extending roller while the opposite leg carries a similar but rearwardly extending roller. Both rollers are positioned to simultaneously ride on oppositely sloped longitudinal cam rails extending along the sides of the slide. Thus, as the slide recoils, the actuator is pivoted in a clockwise direction and as the slide `returns to the battery position thereof, the actuator is pivoted in a counterclockwise direction. This pivotal movement of the actuator is utilized to reciprocate a longitudinally slidable cam plate which, in turn, actuates a pivotal feed lever to impart transverse reciprocal movement to a belt feed pawl in a conventional manner.

Since the slide is arranged to lie beneath the barrel with the cam rails thereon protruding from the front end of the receiver, the actuator can be conveniently mounted forwardly of the breech end of the barrel. Thus, the pivotal movement imparted to the actuator by the recoil of the slide is utilized to pull the cam plate forwardly thereby permitting the belt feed lever to be pivoted at a point forwardly of the feedway in the receiver and still possess suiiicient length to provide the leverage necessary to actuate the belt feeding pawl even under maximum feeding loads. Since this arrangement permits actuation of the cartridge feed mechanism immediately upon the start of the recoil movement of the slide, it is not necessary to include the initial dwell period ordinarily provided to permit the unlocking of the bolt. Consequently, the feeding movement imparted to the cartridge belt can be accomplished with a bolt of reduced size whose recoil travel need be only slightly greater than the length of the cartridge thereby permitting a substantial reduction in the length of the receiver rearwardly of the feedway therein.

Further objects and advantages of the invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration only and in which:

FIG. 1 is a longitudinal side view of the gun partially broken away to show the slide and the bolt in battery position prior to the initiation of the feeding movement imparted to the cartridge belt;

FIG. 2 is a sectional view taken along line 2-2 in FIG. 1 and enlarged to show the structure in greater detail;

FIG. 3 is a transverse section taken along line 3 3 in FIG. 2 to show the position of the components of the cartridge belt feeding mechanism as seen when looking forwardly from within the feedway in the receiver;

FIG. 4 is a transverse section taken along line 4 4 in FIG. 1 to show the manner in which the cam plate actuthereof;

FIG. 5 is a longitudinal view similar to that of FIG. 1 but showing the relative positions of the parts at the conclusion of the recoil movement of the slide;

FIG. 6 is a perspective view of the pivotal actuator utilized to reciprocate the feed cam plate; and

FIG. 7 is a perspective view of the slide on the same scale of FIG. 1.

As illustrated in the drawings, the gun in which the present invention is incorporated includes a receiver 12 in the forward end of which a barrel 14 is xedly secured by means of interrupted locking lugs 16. A bolt 18 is slidably mounted in receiver 12 in axial alignment with barrel 14 and to this end bolt 18 is provided with a depending rear end 20 having a longitudinal rib 22 along each side thereof for slidable engagement with a corresponding groove 24 in the side of receiver 12. Bolt 18 is also provided with a pair of locks 26 pivoted in opposite sides thereof in position to be cammed outwardly, during the return of the recoiling parts to battery position, in front of correspondingly positioned abutments 28 fixed to the interior walls of receiver 12. Forwardly of depending rear end 20, bolt 18 is formed with a T-bar portion 30 along the underside thereof for slidable engagement in a corresponding T-slot 32 provided in the top of a slide 34 mounted for reciprocation in receiver 12 below barrel 14 by means of longitudinal ribs 36 engageable in receiver grooves 24.

As best shown in FIG. 7, T-Slot 32 extends forwardly from the rear end of slide 34 for a distance slightly in excess of the travel required to completely unlock bolt 18 for recoil movement thereof. A pair of cam slots 38 flank T-slot 32 and extend forwardly along the top of slide 34 to terminate in outwardly angled sections 40 disposed substantially midway of the length of T-slot 32. Cam slots 38 are of suicient width to engage a diamondshaped follower stud 42 (FIG. 1) depending from the underside of each bolt lock 26 whereby the locking and unlocking of bolt 18 is controlled by the reciprocation of slide 34. The opposite sides of slide 34 are respectively provided with cam rails 44 and 46 which extend forwardly therealong immediately above and adjacent to ribs 3.6. In order to permit maximum travel of slide 34 in a minimum length of receiver 12, slide 34 is formed with a body portion 47 which, although of suflicient length to maintain contact between T-slot 32 therein and the T- bar portion 30 of bolt 18 in the forwardmost position of slide 34, is nevertheless considerably shorter than cam rails 44 and 46. In addition, the front end of receiver 12 is provided with a pair of openings 48 (FIG. l) which are spaced apart to permit the passage of cam rails 44 and 46 therethrough as slide 34 returns to the fully forward position thereof. Consequently, the forward half of slide body portion 47 is reduced in height, as indicated at 49, to clear locking lugs 16 on barrel 14. Slide body portion 47 is also forwardly bored, as shown at 50, to form spaced apart seats for a pair of operating springs 52 which are of sufficient length to extend into openings 54 in the depending rear end 20 of bolt 18 and bear against the rear wall in receiver 12.

In order to provide a floor for a belt of linked cartridges 56, receiver 12 is provided with a transverse feedway 58 disposed rearwardly of barrel 14 and immediately above the path of travel of bolt 18. Access to the top of feedway 58 is normally prevented by a cover 60 which is pivoted at the forward end thereof to receiver 12 and is adapted to be retained in the closed position thereof by a latch 62 at the rear end thereof. The underside of cover 60 is transversely slotted adjacent the rear end thereof to form a track 64 for slidably receiving a feed slide 66. As best shown in FIG. 3, a pawl 68 is pivoted .to the underside of feed slide 66 at the outer end thereof and is normally biased by a suitable torsion spring 70 into position to engage the side of one of the cartridges 56 in the linked belt. The inner and opposite end of slide 66 is bored, as indicated at 72, to receive one end of a longitudinal coil spring 74. The opposite end of spring 74 is disposed in abutment with the enlarged head of a guide rod 76 seated in a block 78 which is, in turn, iixedly retained in the end of track 64 above the exit portion of feedway 58. The underside of feed slide 66 is suitably grooved, as best shown at 80, in FIG. 2 to engage the rounded rear end 82 of a lever 84 pivotally mounted on a pin 86 depending from the underside of cover 60 at a point slightly forward of the front end of feedway 58.

The forward end of feed lever 84 terminates in a depending follower stud 88 engageable in an angular cam track 90 formed in a substantially rectangular plate 92 slidably mounted in a corresponding rectangular recess 94 longitudinally formed into the top of receiver 12 to extend forwardly of feedway 58 therein. Thus, when plate 92 is reciprocated by means to be described, cam track 90 therein imparts lateral pivotal movement to feed lever 84 which, in turn, actuates feed pawl 68 to advance the leading cartridge 56 in the belt to a position in coaxial alignment with a relatively narrow slit 96 in the center of feedway 58. In this position, the base of such cartridge 56 will be contacted by the front end of a rammer 98 pivoted in bolt 18 to project above the top thereof in response to the bias of a suitable spring (not shown).

The reciprocation required of cam plate 92 is imparted thereto by an inverted U-shaped actuator 100 pivotally secured in receiver 12 to straddle the breech end of barrel 14. The upper end of actuator 100 is formed with a slabbed cylindrical portion 102 adapted to pivotally engage in a transverse slot 104 in the front end of cam plate 92. Each leg of actuator 100 terminates in a foot portion 106 with a mounting hole 108 at the heel end and a roller 110 at the toe and thereof. Each mounting hole 108 in actuator 100 is sized to rotatably receive the reduced diameter end 112 of a transverse pivot stud 114 fixedly secured by any suitable means in the sidewalls of receiver 12. Rollers 110 are each mounted on a transverse pin 116 suitably xed in each toe end of actuator 100 which, as best shown at 118 in FIG. 6, is reduced in width by an amount substantially equivalent to the width of roller 110.

As best shown in FIG. 7, cam rail 44 on the left side of slide 34 is formed with a section 120 of minimum height at the front end thereof which extends rearwardly in parallelism with rib 36 thereon and blends into an upwardly sloped section 122 which leads into a second section 124 parallel to rib 36. Rearwardly of section 124, cam rail 44 is formed with a continued upward slope 126 which extends into a third section 128 parallel to rib 36 and terminates at a point spaced forwardly of the front end of outwardly angled cam slot 40. Rail 46 on the right hand of slide 34 is -similarly contoured except that cam sections 132 and 136 thereon are inversely sloped relative to cam sections 122 `and 126. In addition, since roller 110 on the right leg of actuator 100 is disposed rearwardly of the roller 110 `on the left leg thereof, sections 134 and 138 are located rearwardly of corresponding sections 124 and 128 by an amount substantially equivalent to the longitudinal distance between the centers of rollers 110. In order to maintain this spacing between the corresponding sections of rails 44 and 46, the length of section 130 is increased over that of section and section 138 is terminated at a point adjacent the forward end of outwardly angled cam slot 40.

Thus, in the battery positions of bolt 18 and slide 34, the difference in height at the rear ends of rails 44 and 46 positions actuator 100 so that the portion thereof above pivot studs 114 is tilted rearwardly as best shown in FIG. l. As slide 34 begins to recoil in response to the impact of a gas-operated piston (not shown) against the front face of body portion 47, the rearward travel of cam sections 126 and 236 begins to pivot actuator 100 in a clockwise direction -about pivot studs 114 in receiver 12. As a result, cam plate 92 is pulled forwardly suftciently to bring the angular portion of cam track 90 into engagement with follower stud 88 on belt lfeed lever 84. This initial pivoting of actuator 100 is momentarily interrupted as parallel sections 124 and 134 are moved into engagement with rollers 110 and, during this dwell period, the outwardly angled sections 40 of cam slots 38 in slide 34 pivot bolt locks 26 out of engagement with xed abutments 28 in receiver 12 to unlock bolt 18 for recoil movement together with slide 34.

As cam sections 122 and 132 move into engagement with rollers 110, the previous clockwise pivotal movement of actuator 100 is again continued, pulling cam plate 92 forwardly to the position shown in FIG. 5. During this portion of the pivotal movement of actuator 100, belt feed lever 84 is pivoted to ladvance belt feed pawl 68 inwardly along cartridge feedway 58 and carry the leading cartridge 56 in the linked belt into coaxial alignment with the longitudinal slit 96. As this is accomplished, parallel sections 120 and 130 contact rollers 110 on actuator 100 to provide a dwell period during which the rearward travel of slide 34 to reversed for subsequent counterrecoil movement in response to the energy of compressed operating springs 52.

Actuator 100 is thereupon pivoted in a counterclockwise direction in a manner which is the exact opposite of the movement imparted thereto during the clockwise pivoting thereof. During this counterrecoil movement of slide 34, bolt 1S is advanced therewith so that rammer 98 pushes the leading cartridge 56 in the belt out of the link engaged therewith and into the ring charnber in barrel 14. At the same time, the forward movement of cam plate 92 returns belt feed pawl 68 to the outermost position thereof into engagement with the si-de of the cartridge 56 next adjacent to the one being chambered by bolt 18. At the conclusion lof the forward movement of bolt 18, the continued forward movement of slide 34 brings follower studs 42 -on bolt locks 26 into cam slots 38 to be pivoted into locking engagement with receiver 12. Thus, the recoiling parts of the gun are positioned for the tiring of the next shot in an automatic or semi-automatic manner.

Thus, there is here provided an extremely compact design wherein no more than two components are required to impart the energy of a reciprocating bolt-operating slide to a conventional -belt feed lever. Furthermore, these components are specifically located in the receiver to limit the rearward travel of the slide to that required to position the face of the bolt behind the leading cartridge in the feedway. As a result, the length of that portion of the receiver which includes the cartridge feedway and the space rearwardly thereof is reduced to a minimum. This, of course, results in a gun which can be conveniently mounted in a tank or aircraft in a manner which provides a signicant reduction in the extension thereof into the compartment of the operator without any corresponding decrease in the accessibility of the cartridge feeding mechanism.

Moreover, inasmuch as 4only an actuator and a cam plate are required to transmit the reciprocation of the slide to the belt feed lever, this invention provides an unusually simple and rugged mechanism in comparison to the prior art arrangements which required that a considerable portion of the cartridge feed mechanism extend rearwardly of the feedway in the receiver.

In addition, the concept of pivoting actuator 100 to the interior sidewalls of receiver 12 is particularly noteworthy since it enables the bolt and the slide to be removed from the receiver without the necessity for `disassembly of any portion of the cart-ridge feeding assembly. Thus, the operator `of the gun can accomplish any emergency adjustment of the various components in the bolt such as the extractor, ejector, or rammer without disconnecting the cartridge belt. This is important since firing can be initiated as soon as the gun is assembled Without the additional step of ammunition loading heretofore required in guns of this type.

The present invention has been described in detail above for the purpose of illustration only and is not intended to be limited by this description or otherwise except as defined by the `scope of the appended claims.

I claim:

1. In .an automatic gun having a receiver with a transverse feedway therein for slidably receiving a linked belt of cartridges, a barrel fxedly secured in the forward end of the receiver, a bolt reciprocably disposed in the receiver in coaxial alignment with the barrel, a slide reciprocably disposed in the receiver for imparting recoil and counterrecoil movement to the bolt, and cartridge belt feed mean-s slidably disposed inthe feedway for successive engagement with each leading cartridge in the belt, the improvement in means for actuating said cartridge belt feed means in response to the reciprocating movement of the slide comprising, an actuator pivotally mounted about a transverse axis in the receiver forwardly of the breech end of the barrel, a cam plate slidably disposed in the receiver in simultaneous engagement with said actuator and the cartridge belt feed means, and cam means on the slide engageable with said actuator for imparting pivotal movement thereto and thereby reciprocating said cam plate to actuate the cartridge belt feed means for advancing the leading cartridge in the belt along the feedway into the counterrecoil path of the bolt.

2. The combination defined in claim 1 wherein said cam means on the slide comprises a rail extending along each side thereof and wherein said actuator is provided with rollers engageable with said rails.

3. In an automatic gun having a receiver with a transverse feedway therein for slidably receiving a linked belt of cartridges, a barrel fxedly secured in the forward end of the receiver, a bolt reciprocally disposed in the receiver in coaxial alignment with the barrel, a slide reciprocally disposed in the receiver for imparting recoil and counterrecoil movement to the bolt in response to the firing of a cartridge, cartridge belt feed means slidably disposed in the receiver for successive engagement with each leading cartridge in the belt, and a lever pivoted on a vertical pin in the receiver for actuating the cartridge feed means to position each leading cartridge into the counterrecoil path -of the bolt, the improvement in means for pivoting the cartridge belt feed lever, comprising an actuator pivotally mounted in the receiver for reciprocal movement about a transverse axis and having a pair of oppositely spaced legs straddling the barrel forwardly of the breech end thereof, a cam plate slidably disposed in the receiver above the barrel for simultaneous engagement with the upper end of said actuator and the forward end of the belt feed lever, said actuator legs terminating in respective forwardly and rearwardly extending rollers, and a cam rail longitudinally disposed along opposite sides of the slide for contact with said rollers, said cam rails being inversely sloped whereby the reciprocation of the slide pivots said actuator to reciprocate said cam plate and impart reciprocal pivotal movement to the cartridge belt feed lever.

4. The combination defined in claim 3 wherein said cam plate includes an angular cam track and wherein the belt feed lever is provided with a depending follower stud at the forward end thereof slidably engageable in said angular cam track.

5. In an automatic gun having a receiver with a transverse feedway therein for slidably receiving a linked belt of cartridges, a barrel xedly secured in the forward end of the receiver, a bolt slidably disposed in the receiver in coaxial alignment with the barrel for reciprocating movement into and out of locked battery position, a slide recipr-ocably disposed in the receiver for imparting recoil and counterrecoil movement to the bolt in response to the firing of a cartridge, cartridge belt feed means slidably disposed in the receiver for succes-sive engagement with each leading cartridge in the belt, and a longitudinal lever pivoted on a vertical pin fixed in the receiver ata point above the forward sidewall of the transverse cartridge belt feedway, the improvement in means for pivoting the cartridge belt feed lever to actuate said cartridge belt feed means, comprising an inverted U-shaped actuator having a pair of spaced legs pivotally mounted about a transver-se axis in the receiver in position to straddle the barrel forwardly of the breech end thereof, said legs having respectively oppositely extending feet terminating in roller ends, a longitudinal cam plate having an angular cam track therein, a depending follower stud at the forward end of the cartridge belt feed lever, -said cam plate being slidably disposed in the receiver in pivotal engagement with the upper end of said actuator and with said cam track in slidable engagement with said follower stud on the belt feed lever, and a cam rail extending longitudinally along each side of the slide for slidable engagement with said roller ends on said actuator, said cam rails being inversely sloped at locations which are relatively displaced longitudinally for a distance equivalent to the corresponding separation between the axial centers of said roller ends on -said actuator feet whereby the longitudinal reciprocation of the slide reverses the respective elevation of said roller ends and thereby pivots said actuator about a transverse axis to impart correspondingly opposite reciprocation to said cam plate and thereby pivot the belt feed lever to actuate the cartridge belt feed means.

6. The combination defined in claim 5 wherein said sloped contour of said cam rails includes linear parallel sections adapted to interrupt the pivotal movement of said actuator during the interval in which the bolt is being locked and unlocked.

7. The combination dened in claim 5 wherein said angular cam track in said cam plate is formed with enlarged portions at each end thereof whereby the initiation and completion of the pivotal movement imparted to the cartridge belt feed lever is delayed to provide overtravel of the slide relative to said cam plate.

References Cited by the Examiner FOREIGN PATENTS 723,469 8/1942 Germany 89/33 BENJAMIN A. BORCHELT, Primary Examiner.

FRED C. MATTERN, IR., Examiner. 

1. IN AN AUTOMATIC GUN HAVING A RECEIVER WITH A TRANSVERSE FEEDWAY THEREIN FOR SLIDABLY RECEIVING A LINKED BELT OF CARTRIDGES, A BARREL FIXEDLY SECURED IN THE FORWARD END OF THE RECEIVER, A BOLT RECIRPOCABLY DISPOSED IN THE RECEIVER IN COAXIAL ALIGNMENT WITH THE BARREL, A SLIDE RECIPROCABLY DISPOSED IN THE RECEIVER FOR IMPARTING RECOIL AND COUNTERRCOIL MOVEMENT TO THE BOLT, AND CARTRIDGE BELT FEED MEANS SLIDABLY DISPOSED IN THE FEEDWAY FOR SUCCESSIVE ENGAGEMENT WITH EACH LEADING CARTRIDGE IN THE BELT, THE IMPROVEMENT IN MEANS FOR ACTUATING SAID CARTRIDGE BELT FEED MEANS IN RESPONSE TO THE RECIPROCATING MOVEMENT OF THE SLIDE COMPRISING, AN ACTUATOR PIVOTALLY MOUNTED ABOUT A TRANSVERSE AXIS IN THE RECEIVER FORWARDLY OF THE BREECH END OF THE BARREL, A CAM PLATE SLIDABLY DISPOSED IN THE RECEIVER IN SIMULTANEOUS ENGAGEMENT WITH SAID ACTUATOR AND THE CARTRIDGE BELT FEED MEANS, AND CAM MEANS ON THE SLIDES ENGAGEABLE WITH SAID ACTUATOR FOR IMPARTING PIVOTAL MOVEMENT THERETO AND THEREBY RECIPROCATING SAID CAM PLATE TO ACTUATE THE CARTRIDGE BELT FEED MEANS FOR ADVANCING THE LEADING CARTRIDGE IN THE BELT ALONG THE FEEDWAY INTO TE COUNTERCOIL PATH OF THE BOLT. 